931 research outputs found
Finite top-mass effects in gluon-induced Higgs production with a jet-veto at NNLO
Effects from a finite top quark mass on the H+n-jet cross section through
gluon fusion are studied for at NNLO/NLO QCD. For this purpose,
sub-leading terms in are calculated. We show that the asymptotic
expansion of the jet-vetoed cross section at NNLO is very well behaved and that
the heavy-top approximation is valid at the five permille level up to jet-veto
cuts of 300 GeV. For the inclusive Higgs+jet rate, we introduce a matching
procedure that allows for a reliable prediction of the top-mass effects using
the expansion in . The quality of the effective field theory to evaluate
differential K-factors for the distribution of the hardest jet is found to be
better than 1-2% as long as the transverse momentum of the jet is integrated
out or remains below about 150 GeV.Comment: 22 pages, 14 figure
Multiplicative Approximations, Optimal Hypervolume Distributions, and the Choice of the Reference Point
Many optimization problems arising in applications have to consider several
objective functions at the same time. Evolutionary algorithms seem to be a very
natural choice for dealing with multi-objective problems as the population of
such an algorithm can be used to represent the trade-offs with respect to the
given objective functions. In this paper, we contribute to the theoretical
understanding of evolutionary algorithms for multi-objective problems. We
consider indicator-based algorithms whose goal is to maximize the hypervolume
for a given problem by distributing {\mu} points on the Pareto front. To gain
new theoretical insights into the behavior of hypervolume-based algorithms we
compare their optimization goal to the goal of achieving an optimal
multiplicative approximation ratio. Our studies are carried out for different
Pareto front shapes of bi-objective problems. For the class of linear fronts
and a class of convex fronts, we prove that maximizing the hypervolume gives
the best possible approximation ratio when assuming that the extreme points
have to be included in both distributions of the points on the Pareto front.
Furthermore, we investigate the choice of the reference point on the
approximation behavior of hypervolume-based approaches and examine Pareto
fronts of different shapes by numerical calculations
production at NNLO including anomalous couplings
In this paper we present a next-to-next-to-leading order (NNLO) QCD
calculation of the processes and that we have implemented in MCFM. Our calculation includes
QCD corrections at NNLO both for the Standard Model (SM) and additionally in
the presence of and anomalous couplings. We compare
our implementation, obtained using the jettiness slicing approach, with a
previous SM calculation and find broad agreement. Focusing on the sensitivity
of our results to the slicing parameter, we show that using our setup we are
able to compute NNLO cross sections with numerical uncertainties of about
, which is small compared to residual scale uncertainties of a few
percent. We study potential improvements using two different jettiness
definitions and the inclusion of power corrections. At TeV we
present phenomenological results and consider as a background to
production. We find that, with typical cuts, the inclusion of
NNLO corrections represents a small effect and loosens the extraction of limits
on anomalous couplings by about .Comment: 30 pages, 14 figure
Modeling structural and electronic properties of nano-scale systems
Computergestütze Modellierung von organischen elektronsichen Materialien durch gezielte Untersuchung mikroskopischer Prozesse und Berechnung molekülspezifischer Materialparameter ermöglicht die effiziente Entwicklung langlebiger, effizienter Bauteile. In dieser Arbeit werden die strukturellen und elektronischen Eigenschaften organischer und metall-organischer Schichten untersucht, sowie effiziente Simulationsmethoden (weiter-)entwickelt
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